The present invention relates to an improved polyarylene sulfide resin composition and a process for producing the same.
In particular, the present invention relates to a polyarylene sulfide resin composition having improved impact resistance and ductility and an excellent surface appearance of the surface of its molding, and a process for producing the same.
Recently a flame-retardant thermoplastic resin having high thermal resistance and chemical resistance has been required as a material for the production of components of electric and electronic appliances and the parts of automobiles and chemical apparatus.
Polyarylene sulfide resins represented by polyphenylene sulfide are among the resins satisfying the above requirements. The demand for polyarylene sulfide resins is expanding, since such resins have good properties for the cost thereof.
However, polyarylene sulfide resins have a serious defect in that such resins have a low ductility and are brittle. It is known that the properties required of engineering plastics, such as strength, rigidity, tenacity and thermal resistance, can be remarkably improved by incorporating a fibrous reinforcing material such as a glass fiber or carbon fiber into the resins.
However, even after incorporation thereinto of fibrous reinforcing material, polyarylene sulfide resins are more brittle than other engineering plastics such as nylon or polyacetal. Thus, the use of polyarylene sulfide resins for various purposes is limited because of the insufficient tenacity, even though such resins have excellent properties.
To solve this problem, the following processes have heretofore been proposed:
(1) a process wherein an .alpha.-olefin copolymer which was graft-copolymerized with 10% by weight or less of an unsaturated carboxylic acid or its anhydride and an epoxy resin are incorporated thereinto (see Japanese Patent Laid-Open No. 207921/1984), PA1 (2) a process wherein an olefinic copolymer comprising an .alpha.-olefin and a glycidyl ester of an .alpha.,.beta.-unsaturated acid is incorporated thereinto (see Japanese Patent Laid-Open No. 189166/1984), and PA1 (3) a process wherein a polyamide resin and an epoxy resin are incorporated thereinto (see Japanese Patent Laid-Open No. 155462/1984). PA1 a process for producing the above-described polyarylene sulfide resin composition characterized in that the components (A), (B) and (C) and, if desired, component (D) are melt-kneaded together under heating for at least 30 seconds. PA1 a process for producing the above-described polyarylene sulfide resin composition characterized in that the components (A), (B) and (C) and, if desired, components (B') and (D) are melt-kneaded together under heating for at least 30 seconds.
However, these processes are still insufficient, since they each have problems.
In the above-described processes (1) and (2), the polyarylene sulfide resin is combined with an olefinic copolymer having an ester bond to improve the tenacity. However, according to the follow-up tests of the inventors, the olefinic copolymer is decomposed in the molding step to make the tenacity of the molding insufficient, since the molding temperature of the polyarylene sulfide resin is as high as 300.degree. to 320.degree. C.
According to the same tests, the above-described process (3) is practically unsatisfactory, since bleeding is observed on the surface of the molding, the state of the surface is bad and the melt flow stability of the composition is quite low.